Apollo 11 REDUX

I wanted to split this out of the flyby topic to make it stay on track....

On July 20, 1969, American astronauts Neil Armstrong (1930-2012) and Edwin “Buzz” Aldrin (1930-) became the first humans ever to land on the moon. About six-and-a-half hours later, Armstrong became the first person to walk on the moon. As he set took his first step, Armstrong famously said, “That’s one small step for man, one giant leap for mankind.”

SpaceX has said two Falcon Heavy launches would be required to carry a manned Dragon to a lunar landing. However, the 53 metric ton payload capacity of a single Falcon Heavy would be sufficient to carry the 40 mT (Earth departure stage + lunar lander) system described below. This would require 30 mT and 10 mT gross mass Centaur-style upper stages. This page gives the cost of a ca. 20 mT Centaur upper stage as $30 million:

Re: Apollo 11 REDUX

I think this image from Nasawatch says it best...

Any how do we turn a Dragon of any version into the Apollo LM scaled to what we know...

While I would like a 3 man mission that would do the flyby and lunar landings..maybe we can do it with 2 as we would not want an extra man just circling the moon while the others get to be on its surface.....

The arrays provide 1,500 to 2,000 Watts of power peaking up to 4,000 Watts. Two Power Buses are part of Dragon’s electrical system, providing 120 VDV and 28 VDC respectively. 4 redundant Lithium-Polymer Batteries provide power during orbital night, ascent and re-entry.

So 2 things that can go from the capsule mass numbers are the parachutes system and the PICA heatshield as these will not be part of Dragon modified for Lunar exploration.

I have read the mass of the heat sheild is in the 2,000kg - 3,000 kg range....Still looking for the parachute numbers....

After we have the modified numbers for what we would call the ascent stage then we can work on the truck to make it into the descent stage.....

Re: Apollo 11 REDUX

What I am thinking of is to use the truck like a lunar service module and capsule less heat shield for a crew leaving the truck behind on lunar for return. A new descent unit stage would bring the unit to the lunar surface.

Re: Apollo 11 REDUX

Risk aversion for landing or ascending to orbit with regards to engines or fuel type is the same as Apollo and we can not change that the moon has no possibility for survival if you crash and can not make it back to redevous orbit.

Making a lunar ascent vehicle capable of abort would increase launch mass as well as the same for the descent as well. The lunar landing is full retropropulsion no adept possible as there is no atmosphere.

Human Lunar Exploration is a function of two primary variables:•The transportation architecture (“How You Get There”) and•The Surface Mission Architecture (“What You Do There”)These two variables are utterly interrelated, but are often decided without regard to the otherFurther, “What you do there” is often a function of what you can get there!

Re: Apollo 11 REDUX

I have a question. Perhaps GW Johnson could answer. What is the durability of aluminum? The Apollo LM (formerly known as LEM) was built with an aluminum alloy pressure hull so thin it was 5 times the thickness of Reynolds wrap. There was a story that one worker building a LM dropped a screwdriver, which landed blade down. This is on Earth, in Earth gravity, but it pierced the aluminum floor. Another forum stated...

A quick look at my reference data shows that the pressurized cabin web thickness was specified as thin as "0.015 to 0.025" inches thick. About every 3-4 inches the thickness increased to "0.055 to 0.065" inches, centered on ribs of 0.812 inches depth, 0.04 inches wide.

The Apollo LM had an outer hull that acted as micrometeoroid shield. Modern spacecraft such as Dragon use isogrid, which is machined aluminum alloy with thin walls but thicker ribs in a triangular arrangement. The result is isogrid is light with thin walls between ribs, but the structure is quite stiff. The Soviet LK appears to have an aluminum alloy pressure hull that is not isogrid, but spherical with simply thin aluminum alloy walls. Modern space station modules on ISS use aluminum alloy with isogrid, and rather than a second hull for micrometeoroid protection, they have thermal and micrometeoroid blankets with multi-layer insulation and an outer covering of the same material as a spacesuit: Orthofabric. The question is how light could we make the hull, and how many pressurization/depressurization cycles could it safely endure. The Apollo LM was rated for 5 depressurizations.

What if we used the same thermal and micrometeoroid blankets as ISS modules? How light could we make the pressure hull? Should we design the hull for limited pressure cycles like Apollo, intend the the lunar lander as expendable? Or design it for more cycles, make it reusable?

Re: Apollo 11 REDUX

Hi RobertDyck:

Your question is deceptively simple. The problem it asks about is quite complex. To answer it is very alloy-specific (including various tempers and/or strain-hardening), and comes from the S-N fatigue curves in Mil Handbook 5. With nearly all the aluminum alloys, there is no safe load below which you can ignore life effects (the DC-3 being the exception that proves the rule). Most of these alloys have ultimate strengths somewhere around 60 ksi, and yield strengths near 15-20 ksi, but to get any significant life at all, you dare not load them to more than something like 5 ksi. Plus, the N's from the S-N curves can be an order of magnitude or two wrong, even if you choose the curve with the more representative style of loading. Says so, right in the handbook. Which is two 5" 3-ring binders.

It also depends upon the kind and location of the loading. I rather doubt that internal pressure sizes very many of the parts. Fixed loads like equipment racks and seats will size a lot of the structure, and moving loads like astronauts' suited weights on their feet will size a lot more structures. Further, that's not for moon gravity, or even Earth gravity, but at flight acceleration loads, which might be as high as 2 gees standing and 4-5 gees seated.

Making integral-rib structures is a very expensive machining or chemical milling business. It's usually cheaper and more effective for everything but cryogenic propellant tanks to use bent sheets reinforced with hat- and Z-sections to make a monocoque structure. Trouble is, riveted assemblies will not be gas tight. Welded assemblies restrict your choice of alloy as well as reducing you to lowest-temper / annealed heat treat states.

But if you fit your tank with a rubber bladder, you can use riveted construction. But rubber bladders completely rule out cryogenics. That's in part why room temperature storables are so popular with designers.

Complicated, like I said. Sorry.

GW

Last edited by GW Johnson (2017-01-20 13:49:54)

GW JohnsonMcGregor, Texas

"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"

Re: Apollo 11 REDUX

Thank you very much. That answers a lot. But my question was the cabin, not propellant tanks. So cryogenic temperatures are not relevant. The rest is.

Dragon uses an isogrid hull. Not sure how it's fabricated, whether it's mechanically or chemically machined, but I'm sure you're aware of it. However, one interesting thing about the LM is astronauts will not be in it during launch. Only installed equipment. Astronaut body weight loading is only a factor during lunar descent and landing. That has lower acceleration. When NASA and their contractor designed the LM for Apollo, they found seats were not necessary. They only installed strap loops on the floor for astronauts to hook their feet into. They stood during deorbit, descent, and landing.

I'm thinking of simplifying hull design by using modern 21st century techniques. The Apollo LM had a double wall with gap, so the outer wall would shield against micrometeorites, and larger micrometeorites would fragment before striking the outer surface of the inner hull. I would like to use the same thermal and micrometeor shielding blankets that ISS modules use. ISS uses an isogrid hull. Could we get away with a thinner, lighter hull? Especially if the LM is treated as expendable, single mission only.

The Soviet LK used a spherical hull. That implies the hull need not be wafer at all, just sheet metal. But you would need wafer for the floor. Perhaps wafer aluminum alloy with "Z" ribs welded between two sheets? The Apollo LM used aluminum alloy wafer, although I don't know how it was fabricated. Of course that means a lot of welding. And you have to ensure none of the welds compromise the aluminum sheet that is the pressure tight inner wall. But again, Apollo did it.

Re: Apollo 11 REDUX

The Red Dragon - MSL Hybrid landing architecture would be capable of landing a 1000 kg payload on Mars. Table 1 lists key mission parameters. With a 7200 kg entry mass, the vehicle would be configured by a center of gravity offset to fly with an L/D of 0.24, matching the MSL L/D. Just prior to powered descent, 120 kg of ballast mass (a potential science package mission of opportunity) would be ejected to remove this CG offset , there by balancing the vehicle. During powered decent, 1900 kg of propellant would provide the Δv required for soft landing. System total landed mass would be 5180 kg

Re: Apollo 11 REDUX

Just resurrecting this thread in the light of recent speculation regarding President Trump calling for a return to the Moon in THREE years. Since SLS will not be ready by then--raising the prospect that his recent meetings with Elon Musk were related to this project. Any thoughts or comments on how this might accelerate development of the Falcon Heavy and a follow-on rocket?

Re: Apollo 11 REDUX

Falcon Heavy is scheduled for its first test flight this year. The first flight of Falcon 9 carried an unmanned Dragon as it's dummy payload. So some of us said we want Falcon Heavy to launch Dragon around the Moon, in a lunar fly-by.

NASA won't let SpaceX launch Dragon v2 until after Orion launches. Obvious bias for the favoured contractor. SpaceX could have launched an unmanned test of Dragon v2 by now.

Dragon v2 to do the same mission profile as Orion EM-1, but Dragon first! Trump could allow it, considering his bias for private enterprise.

Re: Apollo 11 REDUX

I think Lockheed-Martin is "in awe" of Trump, ever since they had to negotiate with him about the F-35 multirole fighters. Ditto Boeing w/r to Air Force 1 Replacements. There are also rumors floating around about Trump raising NASA's budget in order to promote the commercialization of space. Asteroid mining, anyone?In my opinion, all the noise being made by the Chinese about establishment of a permanent base on the Moon has Donald's National Security sensors being tickled.Just idle speculation on my part: Trump will call for an Apollo 8 redux by 2018. Only one game in town, and that's SpaceX.

Re: Apollo 11 REDUX

RobertDyck wrote:

Falcon Heavy is scheduled for its first test flight this year. The first flight of Falcon 9 carried an unmanned Dragon as it's dummy payload. So some of us said we want Falcon Heavy to launch Dragon around the Moon, in a lunar fly-by.

NASA won't let SpaceX launch Dragon v2 until after Orion launches. Obvious bias for the favoured contractor. SpaceX could have launched an unmanned test of Dragon v2 by now.

Dragon v2 to do the same mission profile as Orion EM-1, but Dragon first! Trump could allow it, considering his bias for private enterprise.

Does Donald Trump favor that contractor? Are they his friends? Didn't he just complain about the New Air Force One being too expensive? Why would he want to throw money away just to keep a contractor happy? That doesn't seem like Trump!

Re: Apollo 11 REDUX

The ULA Delta IV Heavy doesn't have the capability to launch enough into LEO, leaving the upcoming Falcon Heavy as the "only game in town," for accomplishing ANYTHING in the near term. Why has Trump met with Elon Musk 3 times since the inauguration?

Re: Apollo 11 REDUX

Oldfart1939 wrote:

I think Lockheed-Martin is "in awe" of Trump, ever since they had to negotiate with him about the F-35 multirole fighters. Ditto Boeing w/r to Air Force 1 Replacements. There are also rumors floating around about Trump raising NASA's budget in order to promote the commercialization of space. Asteroid mining, anyone?In my opinion, all the noise being made by the Chinese about establishment of a permanent base on the Moon has Donald's National Security sensors being tickled.Just idle speculation on my part: Trump will call for an Apollo 8 redux by 2018. Only one game in town, and that's SpaceX.

What exactly are they going to put in orbit around the Moon if they are not going to land anything? Seems to me that three years should be enough time to build a lander. Astronauts could teleoperate remotely space probes on the Moon without that 2.6 second round trip delay, but is that worth sending a human crew over? If SpaceX can land a rocket on a launch pad, surely it must be able to put together a Moon lander, they had Moon lander in the 1960s after all! Perhaps the first thing to do would be to deploy a GPS/Comsat system for the Moon, so that an astronaut on any point of the Moo' surface can communicate with Mission control and tell his current whereabouts on the Moon,

Re: Apollo 11 REDUX

I believe that "something quick, and within the 1st administration time frame," is what's needed. The Apollo 8 redux would simply be the technology proof of concept demonstrator, to be followed within a year by a Moon landing--Apollo 11 redux. It should also be a no-brainer about building a communications satellite constellation around the Moon, since that seems to be the business that SpaceX is engaged in. Comsats, that is!

Re: Apollo 11 REDUX

And what are the astronauts to do aboard that capsule? Should Donald Trump just sell lottery tickets and the winners get a free trip around the Moon? I think "Alice" would be a good name for the capsule they send around the Moon!

Re: Apollo 11 REDUX

It would demonstrate the ability to do manned deep space flight. They have to do that before they can do a lander, just as they did with Apollo (8, 9, 10). Most importantly, it would show that America still has the ability.

"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

Re: Apollo 11 REDUX

As near as I can tell, Falcon-Heavy/Dragon 2, just as it is, could do a non-orbiting fly-by of the moon along the lines of the von Braun idea visualized in the 1957 Disney feature. It would probably re-start the second stage a second time for precision trans-lunar injection from LEO.

From there, the Super Draco's have around 0.5 to 0.7 km/s delta-vee capability on a capsule-plus-trunk, I'm thinking (no hard data). That's enough for a mid course to achieve precisely the flyby desired, and for a midcourse to achieve precisely the reentry window wanted, but that would deplete away the possibility of a powered landing. Chutes would be needed.

As I understand it, to decelerate into lunar orbit and accelerate back out of it, will require something like 3 km/s delta-vee. That means the trunk would have to be replaced by a service module big propulsion unit. I doubt you could develop and qualify one in a year. Maybe 3.

If you do this service module with a just little extra delta vee to cover the precision midcourse for desired entry window, then you preserve the Super Draco propellant for a propulsive landing on Earth, which is the preferred design landing mode for Dragon 2.

Now, if you add a lander, and send it separately with a second Falcon-Heavy, you can do lunar orbit rendezvous with it, and reprise the Apollo landings.

The lander is more demanding than the service module. Call it 4-5 years to develop and qualify. For 2 Heavy launches at roughly $100M each, per landing on the moon. At launch costs 20% of program costs, we're looking at a nominal $1B for Spacex plus "somebody" to reprise Apollo.

"Somebody" needs to be a different outfit from Spacex. They have enough on their hands. There are two hardware requirements here: a service module to replace the trunk, and a viable lunar lander no heavier than a Dragon 2/Big Service Module. It'll need enough delta vee to achieve orbit, as well as land from orbit and ascend to orbit, plus a tad of rendezvous manuever.

I wonder if the service module the Europeans are providing for NASA's Orion might serve for the big service module that Dragon2 needs? If so, then the only hardware development here is the lander. The service module is just a custom tailoring job.

Having existing commercial launchers and an existing capsule really do make a huge cost difference, don't they?

GW

Last edited by GW Johnson (2017-02-14 16:56:07)

GW JohnsonMcGregor, Texas

"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"